1. Field of the Invention
The present invention relates generally to the field of medical implantation devices and, more particularly, to an improved fiberoptic-guided interstitial seed manual applicator and seed cartridge.
2. Description of the Related Art
Afterloading brachytherapy has been in use since 1960 when it was pioneered in the United States by Ulrich Henschke. In this medical procedure, malignant tumors and the like are treated by surgically implanting radioactive sources ("seeds") in or about the malignant tumor in order to irradiate the malignancy. The term "seed" as used herein is intended to broadly mean an object or body to be implanted within a patient, including, but not limited to radioactive seeds used in brachytherapy procedures.
A variety of different radioactive materials have been used as seeds. For instance, Basil Hilaris was the first to use Iodine-125 for permanent implantation in a tumor. Since then, use of Iodine-125 has persisted, serving as the seeds used in the vast majority of interstitial brachytherapy implants for a host of tissues and organs. More recently, Palladium-103 has been approved for use as an implantable radionuclide and applications using Palladium-103 continue to be explored. Other radioactive materials that have also been used include Radon-222, Gold-198 and Iridium-192.
Precise location and spacing of the implanted seeds is of particular importance in the treatment of such malignant tumors and the like. Poor location or distribution of seeds can result in undesirable concentrations of seeds leading to either an overdosage or underdosage of radiation. As such, conventional interstitial seed implantation is frequently performed through an open surgical incision in the patient. In one conventional technique, hollow needles are inserted into the tumor and the seeds are thereafter placed in the needles while the needles are being retracted to implant or deposit the seeds in the tumor. Popular instruments commonly used today for surgically implanting seeds in or about the tumor include the Henschke, Fletcher-Suit, and Mick applicators, Royal Marsden gold grain gun, and stainless steel needles/hairpins. With few exceptions, however, the basic concept and design behind most of these seed implantation systems have changed little over the years.
In contrast, the last two decades have witnessed remarkable advances in surgical, imaging, and anesthetic practices, as well as new developments in permanent radionuclide source availability. Despite the fact that many surgical procedures are currently accomplished using conventional endoscopes or laparoscopes with minimal or limited incisions into chest, abdominal or pelvic wall tissue, conventional implantation systems have generally failed to combine such a technique with brachytherapy implantation due to a dearth in brachytherapy technology.
While many problems associated with interstitial seed implantation have been addressed by the above-mentioned conventional implantation instruments, there remains a tremendous need to develop an interstitial seed manual applicator that utilizes fiberoptics and is capable of precise implantation of seeds using minimal or limited incisions into chest, abdominal, or pelvic wall tissue of a patient.
In addition, seed handling in connection with brachytherapy has not changed since the inception of this therapeutic approach thirty years ago. Seeds may be ordered from a distributor and typically arrive loose in a protective lead-lined pig. Seed strength and number of seeds are generally communicated on the appropriate paperwork accompanying the seeds. Following delivery of the seeds, however, all further seed handling duties are typically accomplished manually by the radiation oncologist or related technical staff. These duties include seed counting; loading seeds into the appropriate cartridge, needle, or magazine; sterilizing the seeds in their receptacle for use in the operating suite; keeping a running tally of the number of dispensed seeds in the operating room with paper and pencil; surveying of the operating suite following the procedure in order to track possible loose or stray seeds; and frequent switching of empty seed cartridges, needles, and magazine due to limited seed capacity.
Not only is this current seed handling procedure labor-intensive, but it invariably leads to radiation exposure of the personnel involved. In the best of circumstances, seeds can jam or dislodge from their receptacle and become temporarily or permanently misplaced. Sterilization of seeds intraoperatively wastes precious time and maintaining an accurate seed tally can be confusing. Accordingly, there is a tremendous need to develop a device that simplifies seed handling in connection with brachytherapy and minimizes the above-mentioned problems associated with current techniques.